211 



The same young individual has the pali and other features oi 

 the calice most clearly marked. 



The dimensions of the t3^e are: — Height of corallum, 7 

 mm.; length of calice, 7 mm.; breadth of calice, 5 mm. 



Locality, (tc. — Tolerably abundant in the Eocene of the 

 Adelaide bore. Collected by Professor Tajte. 



T. heterocostatus, T. Woods, from Aldinga, and also occiu-- 

 ring in the Adelaide bore, has a similar alternation of broad and^ 

 slender costse, the latter of which correspond tothe septa, while 

 the former are in the interspaces. In his description of this 

 species, Woods considers that the broad costae are continued 

 by septa of the fourth and fifth orders, which slightly project 

 into the fossa as a thin edge,^ but an examination of several 

 specimens leads me to read the calice differently. One of 

 these specimens enables me ailso to state that the columella;, 

 the structure of which AVoods could not determine, is fascicular. 

 2\ heterocostatus is closely allied to T. planicostatus, but differs 

 in shape, as well as in other respects. 



Troehoeyathus Adelaidensis, spec. nov. PL i,, figs. 4a, 6. 



Tlie corallum is free, short, and compressed, especially in- 

 feriorly. The base is slightly concave', and equals or even 

 exceeds the calice in length. The lateral edges are do'ubly 

 curved, being concave just below the calice, and then convex- 

 to the basal extremities. The calice is shallow and elliptical 

 with its axes in the ratio of 100 toi 76. 



The septa are exsert and in six systems with four cycles. 

 Tlie primaries and secondaries are subequal and larger than 

 the tertiaries ; the quaternaries are short thin lamellae. Tlie 

 tertiaries bend towards and join the secondaries; the quater- 

 naries also sometimes unite with the enclosed tertiary. All 

 are beset with pointed granules on tlieir sideis. 



The central fossa is large and the columella is apparently 

 fascicular. Only three specimens of this coral have been 

 found, and the calices of all are much worn. One of them has 

 been rubbed dovim to a level surface, which thus represents a 

 transverse section of the calice a little below its summit (pi. i., 

 fig. 46). The details of the calice given in the text have 

 been worked out from an examination of all three examples. 

 The pali are indistinct, but I judge them to be moderately thin 

 structures and placed before the primary and secondar^^ septa. 



Exteriorly the corals are better preserved, and the structure 

 of the costae can be easily read. They correspond to the septa, 

 and consist of rows of small, transversely elongat-ed granules.- 



* On some Fossil Corals from Aldinga,. Phil. Soc, Adelaide, vol. I , 

 1877, pp. 109, 110, pi. ii., fig. 1. 



